J. Katz et al., ESTIMATION OF DESIGN EFFECTS AND DIARRHEA CLUSTERING WITHIN HOUSEHOLDS AND VILLAGES, American journal of epidemiology, 138(11), 1993, pp. 994-1006
The degree to which diarrheal disease clustered within households and
within villages among preschool age children was examined using data f
rom four population-based prevalence surveys undertaken in Malawi, Zam
bia, Indonesia, and Nepal over the past decade. The design effect for
each cluster survey was calculated using the diarrhea prevalence, the
cluster sizes, and the magnitude of diarrhea clustering within the sam
pling unit (villages). A recently developed statistical method, altern
ating logistic regression, was used to estimate disease associations w
ithin households of up to nine preschool age children residing within
villages of up to 589 such children. Pairwise odds ratios estimating d
iarrhea clustering within villages ranged from 1.03 (95% confidence in
terval (Cl) 1.01-1.07) in Zambia to 2.19 (95% Cl 1.73-2.78) in Indones
ia. The design effects ranged from 2.07 (95% Cl 1.26-3.19) in Zambia t
o 7.93 (95% Cl 5.16-11.52) in Indonesia. Design effects were strongly
dependent on cluster size. The design effects for clusters of size 50
would have ranged from 1.38 to 4.73. Pairwise odds ratios for diarrhea
clustering within households ranged from 1.88 (95% Cl 1.61-2.19) in N
epal to 10.05 (95% Cl 8.46-11.94) in Indonesia, Household odds ratios
were always larger than village odds ratios. The village and household
pairwise odds ratios adjusted for age, the type of latrine used by th
e household, and presence of a market in the village were slightly hig
her than the unadjusted odds ratios. Alternating logistic regression p
rovided useful estimates of disease clustering within villages and hou
sehold while allowing for covariate adjustment.